Retreating glaciers could affect water supplies

Kate Taylor, 13th September 2012

Glaciers in the eastern and central regions of the Himalayas are retreating at an ever-increasing pace, while those in the western Himalayas may even be growing.

A new report from the National Research Council examines how changes to glaciers in the Hindu Kush-Himalayan region, which covers eight countries across Asia, could affect the area's river systems, water supplies, and the South Asian population.

The eastern Himalayas and Tibetan Plateau are warming, and the trend is more pronounced at higher elevations, says the team. Models suggest that desert dust and black carbon, a component of soot, could be accelerating the trend.

The good news is that retreating glaciers over the next few decades probably won't affect water availability at lower altitudes, where monsoon rains and snowmelt are more significant.

However, if the current rate of retreat continues, says the committee, high elevation areas could see changes in water flow in some river basins. This would be particularly noticeable during the dry season, particularly in the west where glacial melt is more important to the river systems.

Melting glaciers could play an important role in maintaining water security during times of drought or similar climate extremes, the committee noted. Water stored as glacial ice could form a type of insurance, adding to streams and rivers when it's most needed.

"Water resources management and provision of clean water and sanitation are already a challenge in the region, and the changes in climate and water availability warrant small-scale adaptations with effective, flexible management that can adjust to the conditions," the committee concludes.

"Current efforts that focus on natural hazard and disaster reduction in the region could offer useful lessons when considering and addressing the potential for impacts resulting from glacial retreat and changes in snowmelt processes in the region."